package numTrees96;

public class NumTrees {
    public int numTrees(int n) {
        //动态规划，分治思想
        int [] dp = new int[n+1];
        dp[0] = 1;
        dp[1] =1;
        for (int i = 2; i <=n ; i++) {
            for (int j = 1; j <=i; j++) {
                dp[i] += dp[j - 1] * dp[i - j];
            }
        }
        return dp[n];
    }

    public static void main(String[] args) {
        NumTrees numTrees = new NumTrees();
        System.out.println(numTrees.numTrees(3));
    }

}
